diff --git a/core-java-8/src/test/java/com/baeldung/java8/lambda/methodreference/Bicycle.java b/core-java-8/src/test/java/com/baeldung/java8/lambda/methodreference/Bicycle.java
new file mode 100644
index 0000000000..760a24d7c2
--- /dev/null
+++ b/core-java-8/src/test/java/com/baeldung/java8/lambda/methodreference/Bicycle.java
@@ -0,0 +1,29 @@
+package com.baeldung.java8.lambda.methodreference;
+
+public class Bicycle {
+
+    private String brand;
+    private Integer frameSize;
+
+    public Bicycle(String brand, Integer frameSize) {
+        this.brand = brand;
+        this.frameSize = frameSize;
+    }
+
+    public String getBrand() {
+        return brand;
+    }
+
+    public void setBrand(String brand) {
+        this.brand = brand;
+    }
+
+    public Integer getFrameSize() {
+        return frameSize;
+    }
+
+    public void setFrameSize(Integer frameSize) {
+        this.frameSize = frameSize;
+    }
+
+}
diff --git a/core-java-8/src/test/java/com/baeldung/java8/lambda/methodreference/BicycleComparator.java b/core-java-8/src/test/java/com/baeldung/java8/lambda/methodreference/BicycleComparator.java
new file mode 100644
index 0000000000..153a7d105a
--- /dev/null
+++ b/core-java-8/src/test/java/com/baeldung/java8/lambda/methodreference/BicycleComparator.java
@@ -0,0 +1,13 @@
+package com.baeldung.java8.lambda.methodreference;
+
+import java.util.Comparator;
+
+public class BicycleComparator implements Comparator<Bicycle> {
+
+    @Override
+    public int compare(Bicycle a, Bicycle b) {
+        return a.getFrameSize()
+            .compareTo(b.getFrameSize());
+    }
+
+}
diff --git a/core-java-8/src/test/java/com/baeldung/java8/lambda/methodreference/MethodReferenceExamples.java b/core-java-8/src/test/java/com/baeldung/java8/lambda/methodreference/MethodReferenceExamples.java
new file mode 100644
index 0000000000..3b9a5ec6ff
--- /dev/null
+++ b/core-java-8/src/test/java/com/baeldung/java8/lambda/methodreference/MethodReferenceExamples.java
@@ -0,0 +1,70 @@
+package com.baeldung.java8.lambda.methodreference;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.BiFunction;
+
+import org.junit.Test;
+
+public class MethodReferenceExamples {
+
+    private static <T> void doNothingAtAll(Object... o) {
+    }
+
+    ;
+
+    @Test
+    public void referenceToStaticMethod() {
+        List<String> messages = Arrays.asList("Hello", "Baeldung", "readers!");
+        messages.forEach((word) -> {
+            System.out.println(word);
+        });
+        messages.forEach(System.out::println);
+    }
+
+    @Test
+    public void referenceToInstanceMethodOfParticularObject() {
+        BicycleComparator bikeFrameSizeComparator = new BicycleComparator();
+        createBicyclesList().stream()
+            .sorted((a, b) -> bikeFrameSizeComparator.compare(a, b));
+        createBicyclesList().stream()
+            .sorted(bikeFrameSizeComparator::compare);
+    }
+
+    @Test
+    public void referenceToInstanceMethodOfArbitratyObjectOfParticularType() {
+        List<Integer> numbers = Arrays.asList(5, 3, 50, 24, 40, 2, 9, 18);
+        numbers.stream()
+            .sorted((a, b) -> Integer.compare(a, b));
+        numbers.stream()
+            .sorted(Integer::compare);
+    }
+
+    @Test
+    public void referenceToConstructor() {
+        BiFunction<String, Integer, Bicycle> bikeCreator = (brand, frameSize) -> new Bicycle(brand, frameSize);
+        BiFunction<String, Integer, Bicycle> bikeCreatorMethodReference = Bicycle::new;
+        List<Bicycle> bikes = new ArrayList<>();
+        bikes.add(bikeCreator.apply("Giant", 50));
+        bikes.add(bikeCreator.apply("Scott", 20));
+        bikes.add(bikeCreatorMethodReference.apply("Trek", 35));
+        bikes.add(bikeCreatorMethodReference.apply("GT", 40));
+    }
+
+    @Test
+    public void limitationsAndAdditionalExamples() {
+        createBicyclesList().forEach(b -> System.out.printf("Bike brand is '%s' and frame size is '%d'%n", b.getBrand(), b.getFrameSize()));
+        createBicyclesList().forEach((o) -> this.doNothingAtAll(o));
+    }
+
+    private List<Bicycle> createBicyclesList() {
+        List<Bicycle> bikes = new ArrayList<>();
+        bikes.add(new Bicycle("Giant", 50));
+        bikes.add(new Bicycle("Scott", 20));
+        bikes.add(new Bicycle("Trek", 35));
+        bikes.add(new Bicycle("GT", 40));
+        return bikes;
+    }
+
+}
diff --git a/core-java-io/src/main/java/com/baeldung/files/ListFiles.java b/core-java-io/src/main/java/com/baeldung/files/ListFiles.java
new file mode 100644
index 0000000000..c5de36270c
--- /dev/null
+++ b/core-java-io/src/main/java/com/baeldung/files/ListFiles.java
@@ -0,0 +1,64 @@
+package com.baeldung.files;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.DirectoryStream;
+import java.nio.file.FileVisitResult;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.SimpleFileVisitor;
+import java.nio.file.attribute.BasicFileAttributes;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class ListFiles {
+    public static final int DEPTH = 1;
+
+    public Set<String> listFilesUsingJavaIO(String dir) {
+        return Stream.of(new File(dir).listFiles())
+            .filter(file -> !file.isDirectory())
+            .map(File::getName)
+            .collect(Collectors.toSet());
+    }
+
+    public Set<String> listFilesUsingFileWalk(String dir, int depth) throws IOException {
+        try (Stream<Path> stream = Files.walk(Paths.get(dir), depth)) {
+            return stream.filter(file -> !Files.isDirectory(file))
+                .map(Path::getFileName)
+                .map(Path::toString)
+                .collect(Collectors.toSet());
+        }
+    }
+
+    public Set<String> listFilesUsingFileWalkAndVisitor(String dir) throws IOException {
+        Set<String> fileList = new HashSet<>();
+        Files.walkFileTree(Paths.get(dir), new SimpleFileVisitor<Path>() {
+            @Override
+            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
+                if (!Files.isDirectory(file)) {
+                    fileList.add(file.getFileName()
+                        .toString());
+                }
+                return FileVisitResult.CONTINUE;
+            }
+        });
+        return fileList;
+    }
+
+    public Set<String> listFilesUsingDirectoryStream(String dir) throws IOException {
+        Set<String> fileList = new HashSet<>();
+        try (DirectoryStream<Path> stream = Files.newDirectoryStream(Paths.get(dir))) {
+            for (Path path : stream) {
+                if (!Files.isDirectory(path)) {
+                    fileList.add(path.getFileName()
+                        .toString());
+                }
+            }
+        }
+        return fileList;
+    }
+
+}
diff --git a/core-java-io/src/test/java/com/baeldung/file/ListFilesUnitTest.java b/core-java-io/src/test/java/com/baeldung/file/ListFilesUnitTest.java
new file mode 100644
index 0000000000..65710121cc
--- /dev/null
+++ b/core-java-io/src/test/java/com/baeldung/file/ListFilesUnitTest.java
@@ -0,0 +1,46 @@
+package com.baeldung.file;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.IOException;
+import java.util.HashSet;
+import java.util.Set;
+
+import org.junit.Test;
+
+import com.baeldung.files.ListFiles;
+
+public class ListFilesUnitTest {
+
+    private ListFiles listFiles = new ListFiles();
+    private String DIRECTORY = "src/test/resources/listFilesUnitTestFolder";
+    private static final int DEPTH = 1;
+    private Set<String> EXPECTED_FILE_LIST = new HashSet<String>() {
+        {
+            add("test.xml");
+            add("employee.json");
+            add("students.json");
+            add("country.txt");
+        }
+    };
+
+    @Test
+    public void givenDir_whenUsingJAVAIO_thenListAllFiles() throws IOException {
+        assertEquals(EXPECTED_FILE_LIST, listFiles.listFilesUsingJavaIO(DIRECTORY));
+    }
+
+    @Test
+    public void givenDir_whenWalkingTree_thenListAllFiles() throws IOException {
+        assertEquals(EXPECTED_FILE_LIST, listFiles.listFilesUsingFileWalk(DIRECTORY,DEPTH));
+    }
+
+    @Test
+    public void givenDir_whenWalkingTreeWithVisitor_thenListAllFiles() throws IOException {
+        assertEquals(EXPECTED_FILE_LIST, listFiles.listFilesUsingFileWalkAndVisitor(DIRECTORY));
+    }
+
+    @Test
+    public void givenDir_whenUsingDirectoryStream_thenListAllFiles() throws IOException {
+        assertEquals(EXPECTED_FILE_LIST, listFiles.listFilesUsingDirectoryStream(DIRECTORY));
+    }
+}
diff --git a/core-java-io/src/test/resources/listFilesUnitTestFolder/country.txt b/core-java-io/src/test/resources/listFilesUnitTestFolder/country.txt
new file mode 100644
index 0000000000..45bfe896dc
--- /dev/null
+++ b/core-java-io/src/test/resources/listFilesUnitTestFolder/country.txt
@@ -0,0 +1 @@
+This is a sample txt file for unit test ListFilesUnitTest
\ No newline at end of file
diff --git a/core-java-io/src/test/resources/listFilesUnitTestFolder/employee.json b/core-java-io/src/test/resources/listFilesUnitTestFolder/employee.json
new file mode 100644
index 0000000000..9e26dfeeb6
--- /dev/null
+++ b/core-java-io/src/test/resources/listFilesUnitTestFolder/employee.json
@@ -0,0 +1 @@
+{}
\ No newline at end of file
diff --git a/core-java-io/src/test/resources/listFilesUnitTestFolder/students.json b/core-java-io/src/test/resources/listFilesUnitTestFolder/students.json
new file mode 100644
index 0000000000..9e26dfeeb6
--- /dev/null
+++ b/core-java-io/src/test/resources/listFilesUnitTestFolder/students.json
@@ -0,0 +1 @@
+{}
\ No newline at end of file
diff --git a/core-java-io/src/test/resources/listFilesUnitTestFolder/test.xml b/core-java-io/src/test/resources/listFilesUnitTestFolder/test.xml
new file mode 100644
index 0000000000..19b16cc72c
--- /dev/null
+++ b/core-java-io/src/test/resources/listFilesUnitTestFolder/test.xml
@@ -0,0 +1 @@
+<xml></xml>
\ No newline at end of file
diff --git a/core-java-lang/src/main/java/com/baeldung/scope/BracketScopeExample.java b/core-java-lang/src/main/java/com/baeldung/scope/BracketScopeExample.java
new file mode 100644
index 0000000000..37ae211dcb
--- /dev/null
+++ b/core-java-lang/src/main/java/com/baeldung/scope/BracketScopeExample.java
@@ -0,0 +1,14 @@
+package org.baeldung.variable.scope.examples;
+
+public class BracketScopeExample {
+
+    public void mathOperationExample() {
+        Integer sum = 0;
+        {
+            Integer number = 2;
+            sum = sum + number;
+        }
+        // compiler error, number cannot be solved as a variable
+        // number++;
+    }
+}
\ No newline at end of file
diff --git a/core-java-lang/src/main/java/com/baeldung/scope/ClassScopeExample.java b/core-java-lang/src/main/java/com/baeldung/scope/ClassScopeExample.java
new file mode 100644
index 0000000000..241c6b466e
--- /dev/null
+++ b/core-java-lang/src/main/java/com/baeldung/scope/ClassScopeExample.java
@@ -0,0 +1,14 @@
+package org.baeldung.variable.scope.examples;
+
+public class ClassScopeExample {
+
+    Integer amount = 0;
+
+    public void exampleMethod() {
+        amount++;
+    }
+
+    public void anotherExampleMethod() {
+        Integer anotherAmount = amount + 4;
+    }
+}
\ No newline at end of file
diff --git a/core-java-lang/src/main/java/com/baeldung/scope/LoopScopeExample.java b/core-java-lang/src/main/java/com/baeldung/scope/LoopScopeExample.java
new file mode 100644
index 0000000000..7bf92a6d26
--- /dev/null
+++ b/core-java-lang/src/main/java/com/baeldung/scope/LoopScopeExample.java
@@ -0,0 +1,18 @@
+package org.baeldung.variable.scope.examples;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class LoopScopeExample {
+
+    List<String> listOfNames = Arrays.asList("Joe", "Susan", "Pattrick");
+
+    public void iterationOfNames() {
+        String allNames = "";
+        for (String name : listOfNames) {
+            allNames = allNames + " " + name;
+        }
+        // compiler error, name cannot be resolved to a variable
+        // String lastNameUsed = name;
+    }
+}
diff --git a/core-java-lang/src/main/java/com/baeldung/scope/MethodScopeExample.java b/core-java-lang/src/main/java/com/baeldung/scope/MethodScopeExample.java
new file mode 100644
index 0000000000..e62c6a2a1c
--- /dev/null
+++ b/core-java-lang/src/main/java/com/baeldung/scope/MethodScopeExample.java
@@ -0,0 +1,13 @@
+package org.baeldung.variable.scope.examples;
+
+public class MethodScopeExample {
+
+    public void methodA() {
+        Integer area = 2;
+    }
+
+    public void methodB() {
+        // compiler error, area cannot be resolved to a variable
+        // area = area + 2;
+    }
+}
\ No newline at end of file
diff --git a/core-java-lang/src/main/java/com/baeldung/scope/NestedScopesExample.java b/core-java-lang/src/main/java/com/baeldung/scope/NestedScopesExample.java
new file mode 100644
index 0000000000..fcd23e5ae0
--- /dev/null
+++ b/core-java-lang/src/main/java/com/baeldung/scope/NestedScopesExample.java
@@ -0,0 +1,12 @@
+package org.baeldung.variable.scope.examples;
+
+public class NestedScopesExample {
+
+    String title = "Baeldung";
+
+    public void printTitle() {
+        System.out.println(title);
+        String title = "John Doe";
+        System.out.println(title);
+    }
+}
\ No newline at end of file
diff --git a/core-java/src/test/java/com/baeldung/bitwiseoperator/test/BitwiseOperatorUnitTest.java b/core-java/src/test/java/com/baeldung/bitwiseoperator/test/BitwiseOperatorUnitTest.java
index d8af4b0833..f74e181e36 100644
--- a/core-java/src/test/java/com/baeldung/bitwiseoperator/test/BitwiseOperatorUnitTest.java
+++ b/core-java/src/test/java/com/baeldung/bitwiseoperator/test/BitwiseOperatorUnitTest.java
@@ -10,7 +10,7 @@ public class BitwiseOperatorUnitTest {
         int value1 = 6;
         int value2 = 5;
         int result = value1 & value2;
-        assertEquals(result, 4);
+        assertEquals(4, result);
     }
 
     @Test
@@ -18,7 +18,7 @@ public class BitwiseOperatorUnitTest {
         int value1 = 6;
         int value2 = 5;
         int result = value1 | value2;
-        assertEquals(result, 7);
+        assertEquals(7, result);
     }
 
     @Test
@@ -26,7 +26,7 @@ public class BitwiseOperatorUnitTest {
         int value1 = 6;
         int value2 = 5;
         int result = value1 ^ value2;
-        assertEquals(result, 3);
+        assertEquals(3, result);
     }
 
     @Test
@@ -40,42 +40,42 @@ public class BitwiseOperatorUnitTest {
     public void givenOnePositiveInteger_whenSignedRightShiftOperator_thenNewDecimalNumber() {
         int value = 12;
         int rightShift = value >> 2;
-        assertEquals(rightShift, 3);
+        assertEquals(3, rightShift);
     }
 
     @Test
     public void givenOneNegativeInteger_whenSignedRightShiftOperator_thenNewDecimalNumber() {
         int value = -12;
         int rightShift = value >> 2;
-        assertEquals(rightShift, -3);
+        assertEquals(-3, rightShift);
     }
 
     @Test
     public void givenOnePositiveInteger_whenLeftShiftOperator_thenNewDecimalNumber() {
         int value = 12;
         int leftShift = value << 2;
-        assertEquals(leftShift, 48);
+        assertEquals(48, leftShift);
     }
 
     @Test
     public void givenOneNegativeInteger_whenLeftShiftOperator_thenNewDecimalNumber() {
         int value = -12;
         int leftShift = value << 2;
-        assertEquals(leftShift, -48);
+        assertEquals(-48, leftShift);
     }
 
     @Test
     public void givenOnePositiveInteger_whenUnsignedRightShiftOperator_thenNewDecimalNumber() {
         int value = 12;
         int unsignedRightShift = value >>> 2;
-        assertEquals(unsignedRightShift, 3);
+        assertEquals(3, unsignedRightShift);
     }
 
     @Test
     public void givenOneNegativeInteger_whenUnsignedRightShiftOperator_thenNewDecimalNumber() {
         int value = -12;
         int unsignedRightShift = value >>> 2;
-        assertEquals(unsignedRightShift, 1073741821);
+        assertEquals(1073741821, unsignedRightShift);
     }
 
 }
diff --git a/core-kotlin/src/test/kotlin/com/baeldung/voidtypes/VoidTypesUnitTest.kt b/core-kotlin/src/test/kotlin/com/baeldung/voidtypes/VoidTypesUnitTest.kt
index 5c285c3135..468352dbed 100644
--- a/core-kotlin/src/test/kotlin/com/baeldung/voidtypes/VoidTypesUnitTest.kt
+++ b/core-kotlin/src/test/kotlin/com/baeldung/voidtypes/VoidTypesUnitTest.kt
@@ -6,7 +6,19 @@ import kotlin.test.assertTrue
 
 class VoidTypesUnitTest {
 
-    fun returnTypeAsVoid(): Void? {
+    // Un-commenting below methods will result into compilation error
+    // as the syntax used is incorrect and is used for explanation in tutorial.	
+
+    //    fun returnTypeAsVoidAttempt1(): Void {
+    //        println("Trying with Void as return type")
+    //    }
+
+    //    fun returnTypeAsVoidAttempt2(): Void {
+    //        println("Trying with Void as return type")
+    //        return null
+    //    }
+
+    fun returnTypeAsVoidSuccess(): Void? {
         println("Function can have Void as return type")
         return null
     }
@@ -36,7 +48,7 @@ class VoidTypesUnitTest {
 
     @Test
     fun givenVoidReturnType_thenReturnsNullOnly() {
-        assertNull(returnTypeAsVoid())
+        assertNull(returnTypeAsVoidSuccess())
     }
 
     @Test
diff --git a/java-collections-maps/src/test/java/com/baeldung/java/map/MultiValuedMapUnitTest.java b/java-collections-maps/src/test/java/com/baeldung/java/map/MultiValuedMapUnitTest.java
new file mode 100644
index 0000000000..67e4a5b0a0
--- /dev/null
+++ b/java-collections-maps/src/test/java/com/baeldung/java/map/MultiValuedMapUnitTest.java
@@ -0,0 +1,204 @@
+package com.baeldung.java.map;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import org.apache.commons.collections4.MultiMapUtils;
+import org.apache.commons.collections4.MultiValuedMap;
+import org.apache.commons.collections4.multimap.ArrayListValuedHashMap;
+import org.apache.commons.collections4.multimap.HashSetValuedHashMap;
+import org.junit.Test;
+
+public class MultiValuedMapUnitTest {
+
+    @Test
+    public void givenMultiValuesMap_whenPuttingMultipleValuesUsingPutMethod_thenReturningAllValues() {
+        MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
+        
+        map.put("key", "value1");
+        map.put("key", "value2");
+        map.put("key", "value2");
+        
+        assertThat((Collection<String>) map.get("key")).containsExactly("value1", "value2", "value2");
+    }
+ 
+    @Test
+    public void givenMultiValuesMap_whenPuttingMultipleValuesUsingPutAllMethod_thenReturningAllValues() {
+        MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
+        
+        map.putAll("key", Arrays.asList("value1", "value2", "value2"));
+        
+        assertThat((Collection<String>) map.get("key")).containsExactly("value1", "value2", "value2");
+    }
+
+    @Test
+    public void givenMultiValuesMap_whenGettingValueUsingGetMethod_thenReturningValue() {
+        MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
+        map.put("key", "value");
+        
+        assertThat((Collection<String>) map.get("key")).containsExactly("value");
+    }
+
+    @Test
+    public void givenMultiValuesMap_whenUsingEntriesMethod_thenReturningMappings() {
+        MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
+        map.put("key", "value1");
+        map.put("key", "value2");
+        
+        Collection<Entry<String, String>> entries = (Collection<Entry<String, String>>) map.entries();
+        
+        for(Map.Entry<String,String> entry : entries) {
+            assertThat(entry.getKey()).contains("key");
+            assertTrue(entry.getValue().equals("value1") || entry.getValue().equals("value2") );
+        }
+    }
+
+    @Test
+    public void givenMultiValuesMap_whenUsingKeysMethod_thenReturningAllKeys() {
+        MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
+        map.put("key", "value");
+        map.put("key1", "value1");
+        map.put("key2", "value2");
+        
+        assertThat(((Collection<String>) map.keys())).contains("key", "key1", "key2");
+    }
+
+    @Test
+    public void givenMultiValuesMap_whenUsingKeySetMethod_thenReturningAllKeys() {
+        MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
+        map.put("key", "value");
+        map.put("key1", "value1");
+        map.put("key2", "value2");
+        
+        assertThat((Collection<String>) map.keySet()).contains("key", "key1", "key2");
+    }
+
+    @Test
+    public void givenMultiValuesMap_whenUsingValuesMethod_thenReturningAllValues() {
+        MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
+        map.put("key", "value");
+        map.put("key1", "value1");
+        map.put("key2", "value2");
+        
+        assertThat(((Collection<String>) map.values())).contains("value", "value1", "value2");
+    }
+
+    @Test
+    public void givenMultiValuesMap_whenUsingRemoveMethod_thenReturningUpdatedMap() {
+        MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
+        map.put("key", "value");
+        map.put("key1", "value1");
+        map.put("key2", "value2");
+        assertThat(((Collection<String>) map.values())).contains("value", "value1", "value2");
+        
+        map.remove("key");
+        
+        assertThat(((Collection<String>) map.values())).contains("value1", "value2");
+    }
+
+    @Test
+    public void givenMultiValuesMap_whenUsingRemoveMappingMethod_thenReturningUpdatedMapAfterMappingRemoved() {
+        MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
+        map.put("key", "value");
+        map.put("key1", "value1");
+        map.put("key2", "value2");
+        assertThat(((Collection<String>) map.values())).contains("value", "value1", "value2");
+        
+        map.removeMapping("key", "value");
+        
+        assertThat(((Collection<String>) map.values())).contains("value1", "value2");
+    }
+
+    @Test
+    public void givenMultiValuesMap_whenUsingClearMethod_thenReturningEmptyMap() {
+        MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
+        map.put("key", "value");
+        map.put("key1", "value1");
+        map.put("key2", "value2");
+        assertThat(((Collection<String>) map.values())).contains("value", "value1", "value2");
+        
+        map.clear();
+        
+        assertTrue(map.isEmpty());
+    }
+
+    @Test
+    public void givenMultiValuesMap_whenUsingContainsKeyMethod_thenReturningTrue() {
+        MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
+        map.put("key", "value");
+        map.put("key1", "value1");
+        map.put("key2", "value2");
+        
+        assertTrue(map.containsKey("key"));
+    }
+
+    @Test
+    public void givenMultiValuesMap_whenUsingContainsValueMethod_thenReturningTrue() {
+        MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
+        map.put("key", "value");
+        map.put("key1", "value1");
+        map.put("key2", "value2");
+        
+        assertTrue(map.containsValue("value"));
+    }
+
+    @Test
+    public void givenMultiValuesMap_whenUsingIsEmptyMethod_thenReturningFalse() {
+        MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
+        map.put("key", "value");
+        map.put("key1", "value1");
+        map.put("key2", "value2");
+        
+        assertFalse(map.isEmpty());
+    }
+
+    @Test
+    public void givenMultiValuesMap_whenUsingSizeMethod_thenReturningElementCount() {
+        MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
+        map.put("key", "value");
+        map.put("key1", "value1");
+        map.put("key2", "value2");
+        
+        assertEquals(3, map.size());
+    }
+
+    @Test
+    public void givenArrayListValuedHashMap_whenPuttingDoubleValues_thenReturningAllValues() {
+        MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
+        
+        map.put("key", "value1");
+        map.put("key", "value2");
+        map.put("key", "value2");
+        
+        assertThat((Collection<String>) map.get("key")).containsExactly("value1", "value2", "value2");
+    }
+
+    @Test
+    public void givenHashSetValuedHashMap_whenPuttingTwiceTheSame_thenReturningOneValue() {
+        MultiValuedMap<String, String> map = new HashSetValuedHashMap<>();
+        
+        map.put("key1", "value1");
+        map.put("key1", "value1");
+        
+        assertThat((Collection<String>) map.get("key1")).containsExactly("value1");
+    }
+
+    @Test(expected = UnsupportedOperationException.class)
+    public void givenUnmodifiableMultiValuedMap_whenInserting_thenThrowingException() {
+        MultiValuedMap<String, String> map = new ArrayListValuedHashMap<>();
+        map.put("key", "value1");
+        map.put("key", "value2");
+        MultiValuedMap<String, String> immutableMap = MultiMapUtils.unmodifiableMultiValuedMap(map);
+        
+        immutableMap.put("key", "value3");
+    }
+    
+
+}
diff --git a/java-strings/pom.xml b/java-strings/pom.xml
index f4fb1c0865..9f89ed6d76 100755
--- a/java-strings/pom.xml
+++ b/java-strings/pom.xml
@@ -95,6 +95,12 @@
             <version>1.4</version>
         </dependency>
 
+        <dependency>
+            <groupId>org.ahocorasick</groupId>
+            <artifactId>ahocorasick</artifactId>
+            <version>0.4.0</version>
+        </dependency>
+
     </dependencies>
 
     <build>
diff --git a/java-strings/src/main/java/com/baeldung/string/MatchWords.java b/java-strings/src/main/java/com/baeldung/string/MatchWords.java
new file mode 100644
index 0000000000..0cad52c320
--- /dev/null
+++ b/java-strings/src/main/java/com/baeldung/string/MatchWords.java
@@ -0,0 +1,83 @@
+package com.baeldung.string;
+
+import org.ahocorasick.trie.Emit;
+import org.ahocorasick.trie.Token;
+import org.ahocorasick.trie.Trie;
+
+import java.util.*;
+import java.util.function.Function;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class MatchWords {
+
+    public static boolean containsWordsIndexOf(String inputString, String[] words) {
+        boolean found = true;
+        for (String word : words) {
+            if (inputString.indexOf(word) == -1) {
+                found = false;
+                break;
+            }
+        }
+        return found;
+    }
+
+    public static boolean containsWords(String inputString, String[] items) {
+        boolean found = true;
+        for (String item : items) {
+            if (!inputString.contains(item)) {
+                found = false;
+                break;
+            }
+        }
+        return found;
+    }
+
+    public static boolean containsWordsAhoCorasick(String inputString, String[] words) {
+        Trie trie = Trie.builder()
+                .onlyWholeWords()
+                .addKeywords(words)
+                .build();
+
+        Collection<Emit> emits = trie.parseText(inputString);
+        emits.forEach(System.out::println);
+
+        boolean found = true;
+        for(String word : words) {
+            boolean contains = Arrays.toString(emits.toArray()).contains(word);
+            if (!contains) {
+                found = false;
+                break;
+            }
+        }
+
+        return found;
+    }
+
+    public static boolean containsWordsPatternMatch(String inputString, String[] words) {
+
+        StringBuilder regexp = new StringBuilder();
+        for (String word : words) {
+            regexp.append("(?=.*").append(word).append(")");
+        }
+
+        Pattern pattern = Pattern.compile(regexp.toString());
+
+        return pattern.matcher(inputString).find();
+    }
+
+    public static boolean containsWordsJava8(String inputString, String[] words) {
+        List<String> inputStringList = Arrays.asList(inputString.split(" "));
+        List<String> wordsList = Arrays.asList(words);
+
+        return wordsList.stream().allMatch(inputStringList::contains);
+    }
+
+    public static boolean containsWordsArray(String inputString, String[] words) {
+        List<String> inputStringList = Arrays.asList(inputString.split(" "));
+        List<String> wordsList = Arrays.asList(words);
+
+        return inputStringList.containsAll(wordsList);
+    }
+}
diff --git a/java-strings/src/test/java/com/baeldung/string/MatchWordsUnitTest.java b/java-strings/src/test/java/com/baeldung/string/MatchWordsUnitTest.java
new file mode 100644
index 0000000000..385aadaa5d
--- /dev/null
+++ b/java-strings/src/test/java/com/baeldung/string/MatchWordsUnitTest.java
@@ -0,0 +1,66 @@
+package com.baeldung.string;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class MatchWordsUnitTest {
+
+    private final String[] words = {"hello", "Baeldung"};
+    private final String inputString = "hello there, Baeldung";
+    private final String wholeInput = "helloBaeldung";
+
+    @Test
+    public void givenText_whenCallingStringContains_shouldMatchWords() {
+        final boolean result = MatchWords.containsWords(inputString, words);
+        assertThat(result).isTrue();
+    }
+
+    @Test
+    public void givenText_whenCallingJava8_shouldMatchWords() {
+        final boolean result = MatchWords.containsWordsJava8(inputString, words);
+        assertThat(result).isTrue();
+    }
+
+    @Test
+    public void givenText_whenCallingJava8_shouldNotMatchWords() {
+        final boolean result = MatchWords.containsWordsJava8(wholeInput, words);
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    public void givenText_whenCallingPattern_shouldMatchWords() {
+        final boolean result = MatchWords.containsWordsPatternMatch(inputString, words);
+        assertThat(result).isTrue();
+    }
+
+    @Test
+    public void givenText_whenCallingAhoCorasick_shouldMatchWords() {
+        final boolean result = MatchWords.containsWordsAhoCorasick(inputString, words);
+        assertThat(result).isTrue();
+    }
+
+    @Test
+    public void givenText_whenCallingAhoCorasick_shouldNotMatchWords() {
+        final boolean result = MatchWords.containsWordsAhoCorasick(wholeInput, words);
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    public void givenText_whenCallingIndexOf_shouldMatchWords() {
+        final boolean result = MatchWords.containsWordsIndexOf(inputString, words);
+        assertThat(result).isTrue();
+    }
+
+    @Test
+    public void givenText_whenCallingArrayList_shouldMatchWords() {
+        final boolean result = MatchWords.containsWordsArray(inputString, words);
+        assertThat(result).isTrue();
+    }
+
+    @Test
+    public void givenText_whenCallingArrayList_shouldNotMatchWords() {
+        final boolean result = MatchWords.containsWordsArray(wholeInput, words);
+        assertThat(result).isFalse();
+    }
+}
diff --git a/lombok/README.md b/lombok/README.md
index bd6282fd18..e3d08d4e26 100644
--- a/lombok/README.md
+++ b/lombok/README.md
@@ -5,3 +5,5 @@
 - [Lombok @Builder with Inheritance](https://www.baeldung.com/lombok-builder-inheritance)
 - [Lombok Builder with Default Value](https://www.baeldung.com/lombok-builder-default-value)
 - [Lombok Builder with Custom Setter](https://www.baeldung.com/lombok-builder-custom-setter)
+- [Setting up Lombok with Eclipse and Intellij](https://www.baeldung.com/lombok-ide)
+
diff --git a/patterns/principles/solid/pom.xml b/patterns/principles/solid/pom.xml
new file mode 100644
index 0000000000..825c7730a5
--- /dev/null
+++ b/patterns/principles/solid/pom.xml
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.baeldung</groupId>
+    <artifactId>solid/artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+
+    <dependencies>
+        <!-- https://mvnrepository.com/artifact/junit/junit -->
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.12</version>
+            <scope>test</scope>
+        </dependency>
+
+    </dependencies>
+
+</project>
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/d/Keyboard.java b/patterns/principles/solid/src/main/java/com/baeldung/d/Keyboard.java
new file mode 100644
index 0000000000..acb50cedb4
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/d/Keyboard.java
@@ -0,0 +1,4 @@
+package com.baeldung.d;
+
+public class Keyboard {
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/d/Monitor.java b/patterns/principles/solid/src/main/java/com/baeldung/d/Monitor.java
new file mode 100644
index 0000000000..c0ab7a53b2
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/d/Monitor.java
@@ -0,0 +1,6 @@
+package com.baeldung.d;
+
+public class Monitor {
+
+
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/d/Windows98Machine.java b/patterns/principles/solid/src/main/java/com/baeldung/d/Windows98Machine.java
new file mode 100644
index 0000000000..a9f130aedb
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/d/Windows98Machine.java
@@ -0,0 +1,15 @@
+package com.baeldung.d;
+
+public class Windows98Machine {
+
+  private final Keyboard keyboard;
+  private final Monitor monitor;
+
+  public Windows98Machine() {
+
+    monitor = new Monitor();
+    keyboard = new Keyboard();
+
+  }
+
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/d/Windows98MachineDI.java b/patterns/principles/solid/src/main/java/com/baeldung/d/Windows98MachineDI.java
new file mode 100644
index 0000000000..2a6fd74a41
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/d/Windows98MachineDI.java
@@ -0,0 +1,12 @@
+package com.baeldung.d;
+
+public class Windows98MachineDI {
+
+  private final Keyboard keyboard;
+  private final Monitor monitor;
+
+  public Windows98MachineDI(Keyboard keyboard, Monitor monitor) {
+    this.keyboard = keyboard;
+    this.monitor = monitor;
+  }
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/i/BearCarer.java b/patterns/principles/solid/src/main/java/com/baeldung/i/BearCarer.java
new file mode 100644
index 0000000000..3d69211674
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/i/BearCarer.java
@@ -0,0 +1,12 @@
+package com.baeldung.i;
+
+public class BearCarer implements BearCleaner, BearFeeder {
+
+  public void washTheBear() {
+    //I think we missed a spot..
+  }
+
+  public void feedTheBear() {
+    //Tuna tuesdays..
+  }
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/i/BearCleaner.java b/patterns/principles/solid/src/main/java/com/baeldung/i/BearCleaner.java
new file mode 100644
index 0000000000..e2b71b2ce8
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/i/BearCleaner.java
@@ -0,0 +1,5 @@
+package com.baeldung.i;
+
+public interface BearCleaner {
+  void washTheBear();
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/i/BearFeeder.java b/patterns/principles/solid/src/main/java/com/baeldung/i/BearFeeder.java
new file mode 100644
index 0000000000..5d0ba7cd29
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/i/BearFeeder.java
@@ -0,0 +1,5 @@
+package com.baeldung.i;
+
+public interface BearFeeder {
+  void feedTheBear();
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/i/BearKeeper.java b/patterns/principles/solid/src/main/java/com/baeldung/i/BearKeeper.java
new file mode 100644
index 0000000000..f09774a5ff
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/i/BearKeeper.java
@@ -0,0 +1,9 @@
+package com.baeldung.i;
+
+public interface BearKeeper {
+
+  void washTheBear();
+  void feedTheBear();
+  void petTheBear();
+
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/i/BearPetter.java b/patterns/principles/solid/src/main/java/com/baeldung/i/BearPetter.java
new file mode 100644
index 0000000000..a913cf3d8a
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/i/BearPetter.java
@@ -0,0 +1,5 @@
+package com.baeldung.i;
+
+public interface BearPetter {
+  void petTheBear();
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/i/CrazyPerson.java b/patterns/principles/solid/src/main/java/com/baeldung/i/CrazyPerson.java
new file mode 100644
index 0000000000..aae0d4c11b
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/i/CrazyPerson.java
@@ -0,0 +1,8 @@
+package com.baeldung.i;
+
+public class CrazyPerson implements BearPetter {
+
+  public void petTheBear() {
+    //Good luck with that!
+  }
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/l/Car.java b/patterns/principles/solid/src/main/java/com/baeldung/l/Car.java
new file mode 100644
index 0000000000..b3481f894a
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/l/Car.java
@@ -0,0 +1,8 @@
+package com.baeldung.l;
+
+public interface Car {
+
+  void turnOnEngine();
+  void accelerate();
+
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/l/ElectricCar.java b/patterns/principles/solid/src/main/java/com/baeldung/l/ElectricCar.java
new file mode 100644
index 0000000000..fd919c5659
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/l/ElectricCar.java
@@ -0,0 +1,12 @@
+package com.baeldung.l;
+
+public class ElectricCar implements Car {
+
+  public void turnOnEngine() {
+    throw new AssertionError("I don't have an engine!");
+  }
+
+  public void accelerate() {
+    //this acceleration is crazy!
+  }
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/l/Engine.java b/patterns/principles/solid/src/main/java/com/baeldung/l/Engine.java
new file mode 100644
index 0000000000..a8e38b8877
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/l/Engine.java
@@ -0,0 +1,13 @@
+package com.baeldung.l;
+
+public class Engine {
+
+  public void on(){
+    //vroom.
+  }
+
+  public void powerOn(int amount){
+    //do something
+  }
+
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/l/MotorCar.java b/patterns/principles/solid/src/main/java/com/baeldung/l/MotorCar.java
new file mode 100644
index 0000000000..638f315475
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/l/MotorCar.java
@@ -0,0 +1,18 @@
+package com.baeldung.l;
+
+public class MotorCar implements Car {
+
+  private Engine engine;
+
+  //Constructors, getters + setters
+
+  public void turnOnEngine() {
+    //turn on the engine!
+    engine.on();
+  }
+
+  public void accelerate() {
+    //move forward!
+    engine.powerOn(1000);
+  }
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/o/Guitar.java b/patterns/principles/solid/src/main/java/com/baeldung/o/Guitar.java
new file mode 100644
index 0000000000..baab006b5b
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/o/Guitar.java
@@ -0,0 +1,10 @@
+package com.baeldung.o;
+
+public class Guitar {
+
+  private String make;
+  private String model;
+  private int volume;
+
+  //Constructors, getters & setters
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/o/SuperCoolGuitarWithFlames.java b/patterns/principles/solid/src/main/java/com/baeldung/o/SuperCoolGuitarWithFlames.java
new file mode 100644
index 0000000000..b69e3be74a
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/o/SuperCoolGuitarWithFlames.java
@@ -0,0 +1,9 @@
+package com.baeldung.o;
+
+public class SuperCoolGuitarWithFlames extends Guitar {
+
+  private String flameColour;
+
+  //constructor, getters + setters
+
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/s/BadBook.java b/patterns/principles/solid/src/main/java/com/baeldung/s/BadBook.java
new file mode 100644
index 0000000000..03c8fcd488
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/s/BadBook.java
@@ -0,0 +1,27 @@
+package com.baeldung.s;
+
+public class BadBook {
+
+  private String name;
+  private String author;
+  private String text;
+
+  //constructor, getters and setters
+
+
+  //methods that directly relate to the book properties
+  public String replaceWordInText(String word){
+    return text.replaceAll(word, text);
+  }
+
+  public boolean isWordInText(String word){
+    return text.contains(word);
+  }
+
+  //methods for outputting text to console - should this really be here?
+  void printTextToConsole(){
+    //our code for formatting and printing the text
+  }
+
+
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/s/BookPrinter.java b/patterns/principles/solid/src/main/java/com/baeldung/s/BookPrinter.java
new file mode 100644
index 0000000000..0c8ef62e01
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/s/BookPrinter.java
@@ -0,0 +1,13 @@
+package com.baeldung.s;
+
+public class BookPrinter {
+
+  //methods for outputting text
+  void printTextToConsole(String text){
+    //our code for formatting and printing the text
+  }
+
+  void printTextToAnotherMedium(String text){
+    //code for writing to any other location..
+  }
+}
diff --git a/patterns/principles/solid/src/main/java/com/baeldung/s/GoodBook.java b/patterns/principles/solid/src/main/java/com/baeldung/s/GoodBook.java
new file mode 100644
index 0000000000..b0993aca2b
--- /dev/null
+++ b/patterns/principles/solid/src/main/java/com/baeldung/s/GoodBook.java
@@ -0,0 +1,20 @@
+package com.baeldung.s;
+
+public class GoodBook {
+
+  private String name;
+  private String author;
+  private String text;
+
+  //constructor, getters and setters
+
+  //methods that directly relate to the book properties
+  public String replaceWordInText(String word){
+    return text.replaceAll(word, text);
+  }
+
+  public boolean isWordInText(String word){
+    return text.contains(word);
+  }
+
+}
diff --git a/persistence-modules/spring-data-jpa/src/main/java/com/baeldung/passenger/Passenger.java b/persistence-modules/spring-data-jpa/src/main/java/com/baeldung/passenger/Passenger.java
index 24ae47e597..a96b1edb20 100644
--- a/persistence-modules/spring-data-jpa/src/main/java/com/baeldung/passenger/Passenger.java
+++ b/persistence-modules/spring-data-jpa/src/main/java/com/baeldung/passenger/Passenger.java
@@ -25,15 +25,15 @@ class Passenger {
 
     @Basic(optional = false)
     @Column(nullable = false)
-    private int seatNumber;
+    private Integer seatNumber;
 
-    private Passenger(String firstName, String lastName, int seatNumber) {
+    private Passenger(String firstName, String lastName, Integer seatNumber) {
         this.firstName = firstName;
         this.lastName = lastName;
         this.seatNumber = seatNumber;
     }
 
-    static Passenger from(String firstName, String lastName, int seatNumber) {
+    static Passenger from(String firstName, String lastName, Integer seatNumber) {
         return new Passenger(firstName, lastName, seatNumber);
     }
 
@@ -76,7 +76,7 @@ class Passenger {
         return lastName;
     }
 
-    int getSeatNumber() {
+    Integer getSeatNumber() {
         return seatNumber;
     }
 }
diff --git a/persistence-modules/spring-data-jpa/src/test/java/com/baeldung/passenger/PassengerRepositoryIntegrationTest.java b/persistence-modules/spring-data-jpa/src/test/java/com/baeldung/passenger/PassengerRepositoryIntegrationTest.java
index c57e771345..8cd19cec03 100644
--- a/persistence-modules/spring-data-jpa/src/test/java/com/baeldung/passenger/PassengerRepositoryIntegrationTest.java
+++ b/persistence-modules/spring-data-jpa/src/test/java/com/baeldung/passenger/PassengerRepositoryIntegrationTest.java
@@ -1,23 +1,29 @@
 package com.baeldung.passenger;
 
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.contains;
+import static org.hamcrest.core.IsNot.not;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.util.List;
+import java.util.Optional;
+
+import javax.persistence.EntityManager;
+import javax.persistence.PersistenceContext;
+
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
+import org.springframework.data.domain.Example;
+import org.springframework.data.domain.ExampleMatcher;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Sort;
 import org.springframework.test.context.junit4.SpringRunner;
 
-import javax.persistence.EntityManager;
-import javax.persistence.PersistenceContext;
-import java.util.List;
-
-import static org.hamcrest.MatcherAssert.assertThat;
-import static org.hamcrest.Matchers.contains;
-import static org.junit.Assert.assertEquals;
-
 @DataJpaTest
 @RunWith(SpringRunner.class)
 public class PassengerRepositoryIntegrationTest {
@@ -45,7 +51,7 @@ public class PassengerRepositoryIntegrationTest {
         assertEquals(1, passengers.size());
 
         Passenger actual = passengers.get(0);
-        assertEquals(actual, expected);
+        assertEquals(expected, actual);
     }
 
     @Test
@@ -54,16 +60,17 @@ public class PassengerRepositoryIntegrationTest {
 
         Passenger actual = repository.findFirstByOrderBySeatNumberAsc();
 
-        assertEquals(actual, expected);
+        assertEquals(expected, actual);
     }
 
     @Test
     public void givenSeveralPassengersWhenFindPageSortedByThenThePassengerInTheFirstFilledSeatIsReturned() {
         Passenger expected = Passenger.from("Fred", "Bloggs", 22);
 
-        Page<Passenger> page = repository.findAll(PageRequest.of(0, 1, Sort.by(Sort.Direction.ASC, "seatNumber")));
+        Page<Passenger> page = repository.findAll(PageRequest.of(0, 1,
+          Sort.by(Sort.Direction.ASC, "seatNumber")));
 
-        assertEquals(page.getContent().size(), 1);
+        assertEquals(1, page.getContent().size());
 
         Passenger actual = page.getContent().get(0);
         assertEquals(expected, actual);
@@ -94,5 +101,69 @@ public class PassengerRepositoryIntegrationTest {
 
         assertThat(passengers, contains(fred, ricki, jill, siya, eve));
     }
+
+    @Test
+    public void givenPassengers_whenFindByExampleDefaultMatcher_thenExpectedReturned() {
+        Example<Passenger> example = Example.of(Passenger.from("Fred", "Bloggs", null));
+
+        Optional<Passenger> actual = repository.findOne(example);
+
+        assertTrue(actual.isPresent());
+        assertEquals(Passenger.from("Fred", "Bloggs", 22), actual.get());
+    }
+
+    @Test
+    public void givenPassengers_whenFindByExampleCaseInsensitiveMatcher_thenExpectedReturned() {
+        ExampleMatcher caseInsensitiveExampleMatcher = ExampleMatcher.matchingAll().withIgnoreCase();
+        Example<Passenger> example = Example.of(Passenger.from("fred", "bloggs", null),
+          caseInsensitiveExampleMatcher);
+
+        Optional<Passenger> actual = repository.findOne(example);
+
+        assertTrue(actual.isPresent());
+        assertEquals(Passenger.from("Fred", "Bloggs", 22), actual.get());
+    }
+
+    @Test
+    public void givenPassengers_whenFindByExampleCustomMatcher_thenExpectedReturned() {
+        Passenger jill = Passenger.from("Jill", "Smith", 50);
+        Passenger eve = Passenger.from("Eve", "Jackson", 95);
+        Passenger fred = Passenger.from("Fred", "Bloggs", 22);
+        Passenger siya = Passenger.from("Siya", "Kolisi", 85);
+        Passenger ricki = Passenger.from("Ricki", "Bobbie", 36);
+
+        ExampleMatcher customExampleMatcher = ExampleMatcher.matchingAny().withMatcher("firstName",
+          ExampleMatcher.GenericPropertyMatchers.contains().ignoreCase()).withMatcher("lastName",
+          ExampleMatcher.GenericPropertyMatchers.contains().ignoreCase());
+
+        Example<Passenger> example = Example.of(Passenger.from("e", "s", null),
+          customExampleMatcher);
+
+        List<Passenger> passengers = repository.findAll(example);
+
+        assertThat(passengers, contains(jill, eve, fred, siya));
+        assertThat(passengers, not(contains(ricki)));
+    }
+
+    @Test
+    public void givenPassengers_whenFindByIgnoringMatcher_thenExpectedReturned() {
+        Passenger jill = Passenger.from("Jill", "Smith", 50);
+        Passenger eve = Passenger.from("Eve", "Jackson", 95);
+        Passenger fred = Passenger.from("Fred", "Bloggs", 22);
+        Passenger siya = Passenger.from("Siya", "Kolisi", 85);
+        Passenger ricki = Passenger.from("Ricki", "Bobbie", 36);
     
+        ExampleMatcher ignoringExampleMatcher = ExampleMatcher.matchingAny().withMatcher("lastName",
+          ExampleMatcher.GenericPropertyMatchers.startsWith().ignoreCase()).withIgnorePaths("firstName", "seatNumber");
+    
+        Example<Passenger> example = Example.of(Passenger.from(null, "b", null),
+          ignoringExampleMatcher);
+    
+        List<Passenger> passengers = repository.findAll(example);
+    
+        assertThat(passengers, contains(fred, ricki));
+        assertThat(passengers, not(contains(jill)));
+        assertThat(passengers, not(contains(eve)));
+        assertThat(passengers, not(contains(siya)));
+    }
 }
diff --git a/pom.xml b/pom.xml
index 9306a1db2e..68a4a1f7ad 100644
--- a/pom.xml
+++ b/pom.xml
@@ -717,7 +717,6 @@
                 <module>spring-rest-simple</module>
                 <module>spring-resttemplate</module>
                 <module>spring-roo</module>
-                
                 <module>spring-security-acl</module>
                 <module>spring-security-angular/server</module>
                 <module>spring-security-cache-control</module>
diff --git a/spring-boot-libraries/src/main/java/com/baeldung/scheduling/shedlock/TaskScheduler.java b/spring-boot-libraries/src/main/java/com/baeldung/scheduling/shedlock/TaskScheduler.java
index b1b1ad921f..060afe660e 100644
--- a/spring-boot-libraries/src/main/java/com/baeldung/scheduling/shedlock/TaskScheduler.java
+++ b/spring-boot-libraries/src/main/java/com/baeldung/scheduling/shedlock/TaskScheduler.java
@@ -7,9 +7,9 @@ import org.springframework.stereotype.Component;
 @Component
 class TaskScheduler {
 
-    @Scheduled(cron = "*/15 * * * * *")
+    @Scheduled(cron = "*/15 * * * *")
     @SchedulerLock(name = "TaskScheduler_scheduledTask", lockAtLeastForString = "PT5M", lockAtMostForString = "PT14M")
     public void scheduledTask() {
         System.out.println("Running ShedLock task");
     }
-}
\ No newline at end of file
+}
diff --git a/spring-boot-mvc/src/main/java/com/baeldung/scheduling/ScheduleJobsByProfile.java b/spring-boot-mvc/src/main/java/com/baeldung/scheduling/ScheduleJobsByProfile.java
new file mode 100644
index 0000000000..33cd44331f
--- /dev/null
+++ b/spring-boot-mvc/src/main/java/com/baeldung/scheduling/ScheduleJobsByProfile.java
@@ -0,0 +1,20 @@
+package com.baeldung.scheduling;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Profile;
+
+@Configuration
+public class ScheduleJobsByProfile {
+
+    private final static Logger LOG = LoggerFactory.getLogger(ScheduleJobsByProfile.class);
+
+    @Profile("prod")
+    @Bean
+    public ScheduledJob scheduledJob()
+    {
+        return new ScheduledJob("@Profile");
+    }
+}
diff --git a/spring-boot-mvc/src/main/java/com/baeldung/scheduling/ScheduledJob.java b/spring-boot-mvc/src/main/java/com/baeldung/scheduling/ScheduledJob.java
new file mode 100644
index 0000000000..df7cefcd3c
--- /dev/null
+++ b/spring-boot-mvc/src/main/java/com/baeldung/scheduling/ScheduledJob.java
@@ -0,0 +1,21 @@
+package com.baeldung.scheduling;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.scheduling.annotation.Scheduled;
+
+public class ScheduledJob {
+
+    private String source;
+
+    public ScheduledJob(String source) {
+        this.source = source;
+    }
+
+    private final static Logger LOG = LoggerFactory.getLogger(ScheduledJob.class);
+
+    @Scheduled(fixedDelay = 60000)
+    public void cleanTempDir() {
+        LOG.info("Cleaning temp directory via {}", source);
+    }
+}
diff --git a/spring-boot-mvc/src/main/java/com/baeldung/scheduling/ScheduledJobsWithBoolean.java b/spring-boot-mvc/src/main/java/com/baeldung/scheduling/ScheduledJobsWithBoolean.java
new file mode 100644
index 0000000000..b03de61641
--- /dev/null
+++ b/spring-boot-mvc/src/main/java/com/baeldung/scheduling/ScheduledJobsWithBoolean.java
@@ -0,0 +1,28 @@
+package com.baeldung.scheduling;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.scheduling.annotation.Scheduled;
+
+@Configuration
+public class ScheduledJobsWithBoolean {
+
+    private final static Logger LOG = LoggerFactory.getLogger(ScheduledJobsWithBoolean.class);
+
+    @Value("${jobs.enabled:true}")
+    private boolean isEnabled;
+
+    /**
+     * A scheduled job controlled via application property. The job always
+     * executes, but the logic inside is protected by a configurable boolean
+     * flag.
+     */
+    @Scheduled(fixedDelay = 60000)
+    public void cleanTempDirectory() {
+        if(isEnabled) {
+            LOG.info("Cleaning temp directory via boolean flag");
+        }
+    }
+}
diff --git a/spring-boot-mvc/src/main/java/com/baeldung/scheduling/ScheduledJobsWithConditional.java b/spring-boot-mvc/src/main/java/com/baeldung/scheduling/ScheduledJobsWithConditional.java
new file mode 100644
index 0000000000..081c8d990a
--- /dev/null
+++ b/spring-boot-mvc/src/main/java/com/baeldung/scheduling/ScheduledJobsWithConditional.java
@@ -0,0 +1,20 @@
+package com.baeldung.scheduling;
+
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class ScheduledJobsWithConditional
+{
+    /**
+     * This uses @ConditionalOnProperty to conditionally create a bean, which itself
+     * is a scheduled job.
+     * @return ScheduledJob
+     */
+    @Bean
+    @ConditionalOnProperty(value = "jobs.enabled", matchIfMissing = true, havingValue = "true")
+    public ScheduledJob runMyCronTask() {
+        return new ScheduledJob("@ConditionalOnProperty");
+    }
+}
diff --git a/spring-boot-mvc/src/main/java/com/baeldung/scheduling/ScheduledJobsWithExpression.java b/spring-boot-mvc/src/main/java/com/baeldung/scheduling/ScheduledJobsWithExpression.java
new file mode 100644
index 0000000000..577a01f241
--- /dev/null
+++ b/spring-boot-mvc/src/main/java/com/baeldung/scheduling/ScheduledJobsWithExpression.java
@@ -0,0 +1,23 @@
+package com.baeldung.scheduling;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.scheduling.annotation.Scheduled;
+
+@Configuration
+public class ScheduledJobsWithExpression
+{
+   private final static Logger LOG =
+      LoggerFactory.getLogger(ScheduledJobsWithExpression.class);
+
+   /**
+    * A scheduled job controlled via application property. The job always
+    * executes, but the logic inside is protected by a configurable boolean
+    * flag.
+    */
+   @Scheduled(cron = "${jobs.cronSchedule:-}")
+   public void cleanTempDirectory() {
+         LOG.info("Cleaning temp directory via placeholder");
+   }
+}
diff --git a/spring-boot-mvc/src/main/java/com/baeldung/scheduling/SchedulingApplication.java b/spring-boot-mvc/src/main/java/com/baeldung/scheduling/SchedulingApplication.java
new file mode 100644
index 0000000000..913e2137f8
--- /dev/null
+++ b/spring-boot-mvc/src/main/java/com/baeldung/scheduling/SchedulingApplication.java
@@ -0,0 +1,16 @@
+package com.baeldung.scheduling;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.scheduling.annotation.EnableScheduling;
+
+@SpringBootApplication
+@EnableScheduling
+public class SchedulingApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(SchedulingApplication.class, args);
+    }
+
+}
+
diff --git a/spring-boot-rest/pom.xml b/spring-boot-rest/pom.xml
index bcd0381603..cf4ac0371b 100644
--- a/spring-boot-rest/pom.xml
+++ b/spring-boot-rest/pom.xml
@@ -25,31 +25,16 @@
             <groupId>com.fasterxml.jackson.dataformat</groupId>
             <artifactId>jackson-dataformat-xml</artifactId>
         </dependency>
-        <dependency>
-            <groupId>org.hibernate</groupId>
-            <artifactId>hibernate-entitymanager</artifactId>
-        </dependency>
-        <dependency>
-            <groupId>org.springframework</groupId>
-            <artifactId>spring-jdbc</artifactId>
-        </dependency>
-        <dependency>
-            <groupId>org.springframework.data</groupId>
-            <artifactId>spring-data-jpa</artifactId>
-        </dependency>
+      
         <dependency>
             <groupId>com.h2database</groupId>
             <artifactId>h2</artifactId>
         </dependency>
-        <dependency>
-            <groupId>org.springframework</groupId>
-            <artifactId>spring-tx</artifactId>
-        </dependency>
-        <dependency>
-            <groupId>org.springframework.data</groupId>
-            <artifactId>spring-data-commons</artifactId>
-        </dependency>
-
+       <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-jpa</artifactId>
+        </dependency>    
+    
         <!-- util -->
 
         <dependency>
diff --git a/spring-boot-rest/src/main/java/com/baeldung/spring/PersistenceConfig.java b/spring-boot-rest/src/main/java/com/baeldung/spring/PersistenceConfig.java
index 4a4b9eee3f..5179c66978 100644
--- a/spring-boot-rest/src/main/java/com/baeldung/spring/PersistenceConfig.java
+++ b/spring-boot-rest/src/main/java/com/baeldung/spring/PersistenceConfig.java
@@ -25,7 +25,6 @@ import com.google.common.base.Preconditions;
 @EnableTransactionManagement
 @PropertySource({ "classpath:persistence-${envTarget:h2}.properties" })
 @ComponentScan({ "com.baeldung.persistence" })
-// @ImportResource("classpath*:springDataPersistenceConfig.xml")
 @EnableJpaRepositories(basePackages = "com.baeldung.persistence.dao")
 public class PersistenceConfig {
 
diff --git a/spring-boot-rest/src/main/java/com/baeldung/spring/WebConfig.java b/spring-boot-rest/src/main/java/com/baeldung/spring/WebConfig.java
index 39aade174b..80ee975e84 100644
--- a/spring-boot-rest/src/main/java/com/baeldung/spring/WebConfig.java
+++ b/spring-boot-rest/src/main/java/com/baeldung/spring/WebConfig.java
@@ -1,43 +1,10 @@
 package com.baeldung.spring;
 
-import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.ComponentScan;
 import org.springframework.context.annotation.Configuration;
-import org.springframework.http.MediaType;
-import org.springframework.web.servlet.ViewResolver;
-import org.springframework.web.servlet.config.annotation.ContentNegotiationConfigurer;
-import org.springframework.web.servlet.config.annotation.EnableWebMvc;
-import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
 import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
-import org.springframework.web.servlet.view.InternalResourceViewResolver;
+
 
 @Configuration
-@ComponentScan("com.baeldung.web")
-@EnableWebMvc
 public class WebConfig implements WebMvcConfigurer {
 
-    public WebConfig() {
-        super();
-    }
-
-    @Bean
-    public ViewResolver viewResolver() {
-        final InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
-        viewResolver.setPrefix("/WEB-INF/view/");
-        viewResolver.setSuffix(".jsp");
-        return viewResolver;
-    }
-
-    // API
-    @Override
-    public void addViewControllers(final ViewControllerRegistry registry) {
-        registry.addViewController("/graph.html");
-        registry.addViewController("/homepage.html");
-    }
-
-    @Override
-    public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
-        configurer.defaultContentType(MediaType.APPLICATION_JSON);
-    }
-
 }
\ No newline at end of file
diff --git a/spring-boot-rest/src/main/resources/springDataPersistenceConfig.xml b/spring-boot-rest/src/main/resources/springDataPersistenceConfig.xml
deleted file mode 100644
index 5ea2d9c05b..0000000000
--- a/spring-boot-rest/src/main/resources/springDataPersistenceConfig.xml
+++ /dev/null
@@ -1,12 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:jpa="http://www.springframework.org/schema/data/jpa"
-    xsi:schemaLocation="
-    http://www.springframework.org/schema/beans 
-    http://www.springframework.org/schema/beans/spring-beans.xsd
-    http://www.springframework.org/schema/data/jpa 
-    http://www.springframework.org/schema/data/jpa/spring-jpa.xsd"
->
-
-    <jpa:repositories base-package="com.baeldung.persistence.dao"/>
-
-</beans>
\ No newline at end of file
diff --git a/spring-boot/src/main/java/com/baeldung/validation/application/Application.java b/spring-boot/src/main/java/com/baeldung/validation/application/Application.java
new file mode 100644
index 0000000000..af8f768193
--- /dev/null
+++ b/spring-boot/src/main/java/com/baeldung/validation/application/Application.java
@@ -0,0 +1,27 @@
+package com.baeldung.validation.application;
+
+import com.baeldung.validation.application.entities.User;
+import com.baeldung.validation.application.repositories.UserRepository;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+
+@SpringBootApplication
+public class Application {
+    
+    public static void main(String[] args) {
+        SpringApplication.run(Application.class, args);
+    }
+    
+    @Bean
+    public CommandLineRunner run(UserRepository userRepository) throws Exception {
+        return (String[] args) -> {
+            User user1 = new User("Bob", "bob@domain.com");
+            User user2 = new User("Jenny", "jenny@domain.com");
+            userRepository.save(user1);
+            userRepository.save(user2);
+            userRepository.findAll().forEach(System.out::println);
+        };
+    }
+}
diff --git a/spring-boot/src/main/java/com/baeldung/validation/application/controllers/UserController.java b/spring-boot/src/main/java/com/baeldung/validation/application/controllers/UserController.java
new file mode 100644
index 0000000000..a4aeefb70b
--- /dev/null
+++ b/spring-boot/src/main/java/com/baeldung/validation/application/controllers/UserController.java
@@ -0,0 +1,52 @@
+package com.baeldung.validation.application.controllers;
+
+import com.baeldung.validation.application.entities.User;
+import com.baeldung.validation.application.repositories.UserRepository;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import javax.validation.Valid;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.validation.FieldError;
+import org.springframework.web.bind.MethodArgumentNotValidException;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.ResponseStatus;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class UserController {
+
+    private final UserRepository userRepository;
+
+    @Autowired
+    public UserController(UserRepository userRepository) {
+        this.userRepository = userRepository;
+    }
+
+    @GetMapping("/users")
+    public List<User> getUsers() {
+        return (List<User>) userRepository.findAll();
+    }
+
+    @PostMapping("/users")
+    ResponseEntity<String> addUser(@Valid @RequestBody User user) {
+        return ResponseEntity.ok("User is valid");
+    }
+    
+    @ResponseStatus(HttpStatus.BAD_REQUEST)
+    @ExceptionHandler(MethodArgumentNotValidException.class)
+    public Map<String, String> handleValidationExceptions(MethodArgumentNotValidException ex) {
+        Map<String, String> errors = new HashMap<>();
+        ex.getBindingResult().getAllErrors().forEach((error) -> {
+            String fieldName = ((FieldError) error).getField();
+            String errorMessage = error.getDefaultMessage();
+            errors.put(fieldName, errorMessage);
+        });
+        return errors;
+    }
+}
diff --git a/spring-boot/src/main/java/com/baeldung/validation/application/entities/User.java b/spring-boot/src/main/java/com/baeldung/validation/application/entities/User.java
new file mode 100644
index 0000000000..529368f132
--- /dev/null
+++ b/spring-boot/src/main/java/com/baeldung/validation/application/entities/User.java
@@ -0,0 +1,50 @@
+package com.baeldung.validation.application.entities;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.Table;
+import javax.validation.constraints.NotBlank;
+
+@Entity
+public class User {
+    
+    @Id
+    @GeneratedValue(strategy = GenerationType.AUTO)
+    private long id;
+    
+    @NotBlank(message = "Name is mandatory")
+    private String name;
+    
+    @NotBlank(message = "Email is mandatory")
+    private String email;
+    
+    public User(){}
+    
+    public User(String name, String email) {
+        this.name = name;
+        this.email = email;
+    }
+    
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+
+    @Override
+    public String toString() {
+        return "User{" + "id=" + id + ", name=" + name + ", email=" + email + '}';
+    }    
+}
diff --git a/spring-boot/src/main/java/com/baeldung/validation/application/repositories/UserRepository.java b/spring-boot/src/main/java/com/baeldung/validation/application/repositories/UserRepository.java
new file mode 100644
index 0000000000..b579addcaa
--- /dev/null
+++ b/spring-boot/src/main/java/com/baeldung/validation/application/repositories/UserRepository.java
@@ -0,0 +1,8 @@
+package com.baeldung.validation.application.repositories;
+
+import com.baeldung.validation.application.entities.User;
+import org.springframework.data.repository.CrudRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface UserRepository extends CrudRepository<User, Long> {}
diff --git a/spring-boot/src/main/java/org/baeldung/properties/ConfigProperties.java b/spring-boot/src/main/java/org/baeldung/properties/ConfigProperties.java
index 2d3e56100c..3698d8ef30 100644
--- a/spring-boot/src/main/java/org/baeldung/properties/ConfigProperties.java
+++ b/spring-boot/src/main/java/org/baeldung/properties/ConfigProperties.java
@@ -8,7 +8,6 @@ import javax.validation.constraints.Min;
 import javax.validation.constraints.NotBlank;
 import javax.validation.constraints.Pattern;
 
-import org.hibernate.validator.constraints.Length;
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.PropertySource;
@@ -20,41 +19,8 @@ import org.springframework.validation.annotation.Validated;
 @Validated
 public class ConfigProperties {
 
-    @Validated
-    public static class Credentials {
-
-        @Length(max = 4, min = 1)
-        private String authMethod;
-        private String username;
-        private String password;
-
-        public String getAuthMethod() {
-            return authMethod;
-        }
-
-        public void setAuthMethod(String authMethod) {
-            this.authMethod = authMethod;
-        }
-
-        public String getUsername() {
-            return username;
-        }
-
-        public void setUsername(String username) {
-            this.username = username;
-        }
-
-        public String getPassword() {
-            return password;
-        }
-
-        public void setPassword(String password) {
-            this.password = password;
-        }
-    }
-
     @NotBlank
-    private String host;
+    private String hostName;
 
     @Min(1025)
     @Max(65536)
@@ -63,16 +29,16 @@ public class ConfigProperties {
     @Pattern(regexp = "^[a-z0-9._%+-]+@[a-z0-9.-]+\\.[a-z]{2,6}$")
     private String from;
 
-    private Credentials credentials;
     private List<String> defaultRecipients;
     private Map<String, String> additionalHeaders;
+    private Credentials credentials;
 
-    public String getHost() {
-        return host;
+    public String getHostName() {
+        return hostName;
     }
 
-    public void setHost(String host) {
-        this.host = host;
+    public void setHostName(String hostName) {
+        this.hostName = hostName;
     }
 
     public int getPort() {
@@ -91,14 +57,6 @@ public class ConfigProperties {
         this.from = from;
     }
 
-    public Credentials getCredentials() {
-        return credentials;
-    }
-
-    public void setCredentials(Credentials credentials) {
-        this.credentials = credentials;
-    }
-
     public List<String> getDefaultRecipients() {
         return defaultRecipients;
     }
@@ -114,4 +72,12 @@ public class ConfigProperties {
     public void setAdditionalHeaders(Map<String, String> additionalHeaders) {
         this.additionalHeaders = additionalHeaders;
     }
+
+    public Credentials getCredentials() {
+        return credentials;
+    }
+
+    public void setCredentials(Credentials credentials) {
+        this.credentials = credentials;
+    }
 }
diff --git a/spring-boot/src/main/java/org/baeldung/properties/Credentials.java b/spring-boot/src/main/java/org/baeldung/properties/Credentials.java
new file mode 100644
index 0000000000..2d8ac76e62
--- /dev/null
+++ b/spring-boot/src/main/java/org/baeldung/properties/Credentials.java
@@ -0,0 +1,37 @@
+package org.baeldung.properties;
+
+import org.hibernate.validator.constraints.Length;
+import org.springframework.validation.annotation.Validated;
+
+@Validated
+public class Credentials {
+
+    @Length(max = 4, min = 1)
+    private String authMethod;
+    private String username;
+    private String password;
+
+    public String getAuthMethod() {
+        return authMethod;
+    }
+
+    public void setAuthMethod(String authMethod) {
+        this.authMethod = authMethod;
+    }
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+}
diff --git a/spring-boot/src/main/resources/configprops.properties b/spring-boot/src/main/resources/configprops.properties
index e5d9ae621d..2dad11f9cc 100644
--- a/spring-boot/src/main/resources/configprops.properties
+++ b/spring-boot/src/main/resources/configprops.properties
@@ -1,5 +1,5 @@
 #Simple properties
-mail.host=mailer@mail.com
+mail.hostname=host@mail.com
 mail.port=9000
 mail.from=mailer@mail.com
 
diff --git a/spring-boot/src/test/java/com/baeldung/validation/tests/UserControllerIntegrationTest.java b/spring-boot/src/test/java/com/baeldung/validation/tests/UserControllerIntegrationTest.java
new file mode 100644
index 0000000000..265c4ec22c
--- /dev/null
+++ b/spring-boot/src/test/java/com/baeldung/validation/tests/UserControllerIntegrationTest.java
@@ -0,0 +1,69 @@
+package com.baeldung.validation.tests;
+
+import com.baeldung.validation.application.controllers.UserController;
+import com.baeldung.validation.application.repositories.UserRepository;
+import java.nio.charset.Charset;
+import static org.assertj.core.api.Assertions.assertThat;
+import org.hamcrest.core.Is;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
+import org.springframework.boot.test.mock.mockito.MockBean;
+import org.springframework.http.MediaType;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
+import org.springframework.test.web.servlet.result.MockMvcResultMatchers;
+
+@RunWith(SpringRunner.class)
+@WebMvcTest
+@AutoConfigureMockMvc
+public class UserControllerIntegrationTest {
+
+    @MockBean
+    private UserRepository userRepository;
+    
+    @Autowired
+    UserController userController;
+
+    @Autowired
+    private MockMvc mockMvc;
+
+    @Test
+    public void whenUserControllerInjected_thenNotNull() throws Exception {
+        assertThat(userController).isNotNull();
+    }
+
+    @Test
+    public void whenGetRequestToUsers_thenCorrectResponse() throws Exception {
+        mockMvc.perform(MockMvcRequestBuilders.get("/users")
+                .contentType(MediaType.APPLICATION_JSON_UTF8))
+                .andExpect(MockMvcResultMatchers.status().isOk())
+                .andExpect(MockMvcResultMatchers.content().contentType(MediaType.APPLICATION_JSON_UTF8));
+    
+    }
+    
+    @Test
+    public void whenPostRequestToUsersAndValidUser_thenCorrectResponse() throws Exception {
+        MediaType textPlainUtf8 = new MediaType(MediaType.TEXT_PLAIN, Charset.forName("UTF-8"));
+        String user = "{\"name\": \"bob\", \"email\" : \"bob@domain.com\"}";
+        mockMvc.perform(MockMvcRequestBuilders.post("/users")
+                .content(user)
+                .contentType(MediaType.APPLICATION_JSON_UTF8))
+                .andExpect(MockMvcResultMatchers.status().isOk())
+                .andExpect(MockMvcResultMatchers.content().contentType(textPlainUtf8));
+    }
+    
+    @Test
+    public void whenPostRequestToUsersAndInValidUser_thenCorrectReponse() throws Exception {
+        String user = "{\"name\": \"\", \"email\" : \"bob@domain.com\"}";
+        mockMvc.perform(MockMvcRequestBuilders.post("/users")
+                .content(user)
+                .contentType(MediaType.APPLICATION_JSON_UTF8))
+                .andExpect(MockMvcResultMatchers.status().isBadRequest())
+                .andExpect(MockMvcResultMatchers.jsonPath("$.name", Is.is("Name is mandatory")))
+                .andExpect(MockMvcResultMatchers.content().contentType(MediaType.APPLICATION_JSON_UTF8));
+    }
+}
diff --git a/spring-boot/src/test/java/org/baeldung/properties/ConfigPropertiesIntegrationTest.java b/spring-boot/src/test/java/org/baeldung/properties/ConfigPropertiesIntegrationTest.java
index 3f3b558db9..4ba6bf29d8 100644
--- a/spring-boot/src/test/java/org/baeldung/properties/ConfigPropertiesIntegrationTest.java
+++ b/spring-boot/src/test/java/org/baeldung/properties/ConfigPropertiesIntegrationTest.java
@@ -1,5 +1,8 @@
 package org.baeldung.properties;
 
+import java.util.List;
+import java.util.Map;
+
 import org.junit.Assert;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -18,26 +21,36 @@ public class ConfigPropertiesIntegrationTest {
 
     @Test
     public void whenSimplePropertyQueriedthenReturnsProperty() throws Exception {
-        Assert.assertTrue("From address is read as null!", properties.getFrom() != null);
+        Assert.assertEquals("Incorrectly bound hostName property", "host@mail.com", properties.getHostName());
+        Assert.assertEquals("Incorrectly bound port property", 9000, properties.getPort());
+        Assert.assertEquals("Incorrectly bound from property", "mailer@mail.com", properties.getFrom());
     }
 
     @Test
     public void whenListPropertyQueriedthenReturnsProperty() throws Exception {
-        Assert.assertTrue("Couldn't bind list property!", properties.getDefaultRecipients().size() == 2);
-        Assert.assertTrue("Incorrectly bound list property. Expected 2 entries!", properties.getDefaultRecipients().size() == 2);
+        List<String> defaultRecipients = properties.getDefaultRecipients();
+        Assert.assertTrue("Couldn't bind list property!", defaultRecipients.size() == 2);
+        Assert.assertTrue("Incorrectly bound list property. Expected 2 entries!", defaultRecipients.size() == 2);
+        Assert.assertEquals("Incorrectly bound list[0] property", "admin@mail.com", defaultRecipients.get(0));
+        Assert.assertEquals("Incorrectly bound list[1] property", "owner@mail.com", defaultRecipients.get(1));
     }
 
     @Test
     public void whenMapPropertyQueriedthenReturnsProperty() throws Exception {
-        Assert.assertTrue("Couldn't bind map property!", properties.getAdditionalHeaders() != null);
-        Assert.assertTrue("Incorrectly bound map property. Expected 3 Entries!", properties.getAdditionalHeaders().size() == 3);
+        Map<String, String> additionalHeaders = properties.getAdditionalHeaders();
+        Assert.assertTrue("Couldn't bind map property!", additionalHeaders != null);
+        Assert.assertTrue("Incorrectly bound map property. Expected 3 Entries!", additionalHeaders.size() == 3);
+        Assert.assertEquals("Incorrectly bound map[redelivery] property", "true", additionalHeaders.get("redelivery"));
+        Assert.assertEquals("Incorrectly bound map[secure] property", "true", additionalHeaders.get("secure"));
+        Assert.assertEquals("Incorrectly bound map[p3] property", "value", additionalHeaders.get("p3"));
     }
 
     @Test
     public void whenObjectPropertyQueriedthenReturnsProperty() throws Exception {
-        Assert.assertTrue("Couldn't bind map property!", properties.getCredentials() != null);
-        Assert.assertTrue("Incorrectly bound object property!", properties.getCredentials().getAuthMethod().equals("SHA1"));
-        Assert.assertTrue("Incorrectly bound object property!", properties.getCredentials().getUsername().equals("john"));
-        Assert.assertTrue("Incorrectly bound object property!", properties.getCredentials().getPassword().equals("password"));
+        Credentials credentials = properties.getCredentials();
+        Assert.assertTrue("Couldn't bind map property!", credentials != null);
+        Assert.assertEquals("Incorrectly bound object property, authMethod", "SHA1", credentials.getAuthMethod());
+        Assert.assertEquals("Incorrectly bound object property, username", "john", credentials.getUsername());
+        Assert.assertEquals("Incorrectly bound object property, password", "password", credentials.getPassword());
     }
 }
diff --git a/spring-boot/src/test/resources/configprops-test.properties b/spring-boot/src/test/resources/configprops-test.properties
index b27cf2107a..697771ae6e 100644
--- a/spring-boot/src/test/resources/configprops-test.properties
+++ b/spring-boot/src/test/resources/configprops-test.properties
@@ -1,5 +1,5 @@
 #Simple properties
-mail.host=mailer@mail.com
+mail.hostname=host@mail.com
 mail.port=9000
 mail.from=mailer@mail.com
 
diff --git a/spring-cloud/README.md b/spring-cloud/README.md
index eb2e46c3d0..fede3cc12d 100644
--- a/spring-cloud/README.md
+++ b/spring-cloud/README.md
@@ -15,8 +15,6 @@
 ### Relevant Articles:
 - [Intro to Spring Cloud Netflix - Hystrix](http://www.baeldung.com/spring-cloud-netflix-hystrix)
 - [Dockerizing a Spring Boot Application](http://www.baeldung.com/dockerizing-spring-boot-application)
-- [Using a Spring Cloud App Starter](http://www.baeldung.com/using-a-spring-cloud-app-starter)
-- [Using a Spring Cloud App Starter](http://www.baeldung.com/spring-cloud-app-starter)
 - [Instance Profile Credentials using Spring Cloud](http://www.baeldung.com/spring-cloud-instance-profiles)
 - [Running Spring Boot Applications With Minikube](http://www.baeldung.com/spring-boot-minikube)
 
diff --git a/spring-cloud/spring-cloud-stream-starters/README.md b/spring-cloud/spring-cloud-stream-starters/README.md
new file mode 100644
index 0000000000..761d54abbd
--- /dev/null
+++ b/spring-cloud/spring-cloud-stream-starters/README.md
@@ -0,0 +1,3 @@
+#Revelant Articles:
+
+- [Using a Spring Cloud App Starter](http://www.baeldung.com/spring-cloud-app-starter)
diff --git a/spring-data-rest/src/main/java/com/baeldung/config/DbConfig.java b/spring-data-rest/src/main/java/com/baeldung/config/DbConfig.java
index 05fa27bbff..3ca728ec94 100644
--- a/spring-data-rest/src/main/java/com/baeldung/config/DbConfig.java
+++ b/spring-data-rest/src/main/java/com/baeldung/config/DbConfig.java
@@ -20,7 +20,7 @@ import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
 // @PropertySource("persistence-h2.properties")
 // @PropertySource("persistence-hsqldb.properties")
 // @PropertySource("persistence-derby.properties")
-//@PropertySource("persistence-sqlite.properties")
+// @PropertySource("persistence-sqlite.properties")
 public class DbConfig {
 
     @Autowired
@@ -65,21 +65,23 @@ public class DbConfig {
 @Configuration
 @Profile("h2")
 @PropertySource("classpath:persistence-h2.properties")
-class H2Config {}
+class H2Config {
+}
 
 @Configuration
 @Profile("hsqldb")
 @PropertySource("classpath:persistence-hsqldb.properties")
-class HsqldbConfig {}
-
+class HsqldbConfig {
+}
 
 @Configuration
 @Profile("derby")
 @PropertySource("classpath:persistence-derby.properties")
-class DerbyConfig {}
-
+class DerbyConfig {
+}
 
 @Configuration
 @Profile("sqlite")
 @PropertySource("classpath:persistence-sqlite.properties")
-class SqliteConfig {}
+class SqliteConfig {
+}
diff --git a/spring-data-rest/src/main/java/com/baeldung/config/MvcConfig.java b/spring-data-rest/src/main/java/com/baeldung/config/MvcConfig.java
index e5748f2f55..9d0d3a6687 100644
--- a/spring-data-rest/src/main/java/com/baeldung/config/MvcConfig.java
+++ b/spring-data-rest/src/main/java/com/baeldung/config/MvcConfig.java
@@ -11,11 +11,11 @@ import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
 @Configuration
 @EnableWebMvc
 public class MvcConfig implements WebMvcConfigurer {
-    
-    public MvcConfig(){
+
+    public MvcConfig() {
         super();
     }
-    
+
     @Override
     public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
         configurer.enable();
@@ -27,7 +27,7 @@ public class MvcConfig implements WebMvcConfigurer {
     }
 
     @Bean
-    BookEventHandler bookEventHandler(){
+    BookEventHandler bookEventHandler() {
         return new BookEventHandler();
     }
 
diff --git a/spring-data-rest/src/main/java/com/baeldung/config/RestConfig.java b/spring-data-rest/src/main/java/com/baeldung/config/RestConfig.java
index 39f90e867b..47cb95693b 100644
--- a/spring-data-rest/src/main/java/com/baeldung/config/RestConfig.java
+++ b/spring-data-rest/src/main/java/com/baeldung/config/RestConfig.java
@@ -12,10 +12,9 @@ import org.springframework.http.HttpMethod;
 public class RestConfig implements RepositoryRestConfigurer {
 
     @Override
-    public void configureRepositoryRestConfiguration(RepositoryRestConfiguration repositoryRestConfiguration){
+    public void configureRepositoryRestConfiguration(RepositoryRestConfiguration repositoryRestConfiguration) {
         repositoryRestConfiguration.getProjectionConfiguration().addProjection(CustomBook.class);
         ExposureConfiguration config = repositoryRestConfiguration.getExposureConfiguration();
-        config.forDomainType(WebsiteUser.class).withItemExposure((metadata, httpMethods) ->
-          httpMethods.disable(HttpMethod.PATCH));
+        config.forDomainType(WebsiteUser.class).withItemExposure((metadata, httpMethods) -> httpMethods.disable(HttpMethod.PATCH));
     }
 }
diff --git a/spring-data-rest/src/main/java/com/baeldung/config/ValidatorEventRegister.java b/spring-data-rest/src/main/java/com/baeldung/config/ValidatorEventRegister.java
index 8f14d6c1c6..632ad9183a 100644
--- a/spring-data-rest/src/main/java/com/baeldung/config/ValidatorEventRegister.java
+++ b/spring-data-rest/src/main/java/com/baeldung/config/ValidatorEventRegister.java
@@ -24,13 +24,7 @@ public class ValidatorEventRegister implements InitializingBean {
         List<String> events = Arrays.asList("beforeCreate", "afterCreate", "beforeSave", "afterSave", "beforeLinkSave", "afterLinkSave", "beforeDelete", "afterDelete");
 
         for (Map.Entry<String, Validator> entry : validators.entrySet()) {
-            events
-              .stream()
-              .filter(p -> entry
-                .getKey()
-                .startsWith(p))
-              .findFirst()
-              .ifPresent(p -> validatingRepositoryEventListener.addValidator(p, entry.getValue()));
+            events.stream().filter(p -> entry.getKey().startsWith(p)).findFirst().ifPresent(p -> validatingRepositoryEventListener.addValidator(p, entry.getValue()));
         }
     }
 }
diff --git a/spring-data-rest/src/main/java/com/baeldung/events/AuthorEventHandler.java b/spring-data-rest/src/main/java/com/baeldung/events/AuthorEventHandler.java
index 5a8ae05c08..485dc8e221 100644
--- a/spring-data-rest/src/main/java/com/baeldung/events/AuthorEventHandler.java
+++ b/spring-data-rest/src/main/java/com/baeldung/events/AuthorEventHandler.java
@@ -8,33 +8,34 @@ import java.util.logging.Logger;
 
 @RepositoryEventHandler
 public class AuthorEventHandler {
-        Logger logger = Logger.getLogger("Class AuthorEventHandler");
-        public AuthorEventHandler(){
-                super();
-        }
+    Logger logger = Logger.getLogger("Class AuthorEventHandler");
 
-        @HandleBeforeCreate
-        public void handleAuthorBeforeCreate(Author author){
-                logger.info("Inside  Author Before Create....");
-                String name = author.getName();
-        }
+    public AuthorEventHandler() {
+        super();
+    }
 
-        @HandleAfterCreate
-        public void handleAuthorAfterCreate(Author author){
-                logger.info("Inside  Author After Create ....");
-                String name = author.getName();
-        }
+    @HandleBeforeCreate
+    public void handleAuthorBeforeCreate(Author author) {
+        logger.info("Inside  Author Before Create....");
+        String name = author.getName();
+    }
 
-        @HandleBeforeDelete
-        public void handleAuthorBeforeDelete(Author author){
-                logger.info("Inside  Author Before Delete ....");
-                String name = author.getName();
-        }
+    @HandleAfterCreate
+    public void handleAuthorAfterCreate(Author author) {
+        logger.info("Inside  Author After Create ....");
+        String name = author.getName();
+    }
 
-        @HandleAfterDelete
-        public void handleAuthorAfterDelete(Author author){
-                logger.info("Inside  Author After Delete ....");
-                String name = author.getName();
-        }
+    @HandleBeforeDelete
+    public void handleAuthorBeforeDelete(Author author) {
+        logger.info("Inside  Author Before Delete ....");
+        String name = author.getName();
+    }
+
+    @HandleAfterDelete
+    public void handleAuthorAfterDelete(Author author) {
+        logger.info("Inside  Author After Delete ....");
+        String name = author.getName();
+    }
 
 }
diff --git a/spring-data-rest/src/main/java/com/baeldung/events/BookEventHandler.java b/spring-data-rest/src/main/java/com/baeldung/events/BookEventHandler.java
index 3953e6ce0d..36ae62b926 100644
--- a/spring-data-rest/src/main/java/com/baeldung/events/BookEventHandler.java
+++ b/spring-data-rest/src/main/java/com/baeldung/events/BookEventHandler.java
@@ -10,17 +10,18 @@ import org.springframework.data.rest.core.annotation.RepositoryEventHandler;
 
 @RepositoryEventHandler
 public class BookEventHandler {
-        Logger logger = Logger.getLogger("Class BookEventHandler");
-        @HandleBeforeCreate
-        public void handleBookBeforeCreate(Book book){
+    Logger logger = Logger.getLogger("Class BookEventHandler");
 
-                logger.info("Inside Book Before Create ....");
-                book.getAuthors();
-        }
+    @HandleBeforeCreate
+    public void handleBookBeforeCreate(Book book) {
 
-        @HandleBeforeCreate
-        public void handleAuthorBeforeCreate(Author author){
-                logger.info("Inside Author Before Create ....");
-                author.getBooks();
-        }
+        logger.info("Inside Book Before Create ....");
+        book.getAuthors();
+    }
+
+    @HandleBeforeCreate
+    public void handleAuthorBeforeCreate(Author author) {
+        logger.info("Inside Author Before Create ....");
+        author.getBooks();
+    }
 }
diff --git a/spring-data-rest/src/main/java/com/baeldung/exception/handlers/RestResponseEntityExceptionHandler.java b/spring-data-rest/src/main/java/com/baeldung/exception/handlers/RestResponseEntityExceptionHandler.java
index aa24fccac7..a3ef91f6d6 100644
--- a/spring-data-rest/src/main/java/com/baeldung/exception/handlers/RestResponseEntityExceptionHandler.java
+++ b/spring-data-rest/src/main/java/com/baeldung/exception/handlers/RestResponseEntityExceptionHandler.java
@@ -19,12 +19,7 @@ public class RestResponseEntityExceptionHandler extends ResponseEntityExceptionH
     public ResponseEntity<Object> handleAccessDeniedException(Exception ex, WebRequest request) {
         RepositoryConstraintViolationException nevEx = (RepositoryConstraintViolationException) ex;
 
-        String errors = nevEx
-          .getErrors()
-          .getAllErrors()
-          .stream()
-          .map(ObjectError::toString)
-          .collect(Collectors.joining("\n"));
+        String errors = nevEx.getErrors().getAllErrors().stream().map(ObjectError::toString).collect(Collectors.joining("\n"));
         return new ResponseEntity<>(errors, new HttpHeaders(), HttpStatus.NOT_ACCEPTABLE);
     }
 
diff --git a/spring-data-rest/src/main/java/com/baeldung/models/Address.java b/spring-data-rest/src/main/java/com/baeldung/models/Address.java
index 82e3783f3e..713af58ae6 100644
--- a/spring-data-rest/src/main/java/com/baeldung/models/Address.java
+++ b/spring-data-rest/src/main/java/com/baeldung/models/Address.java
@@ -11,7 +11,7 @@ import javax.persistence.OneToOne;
 public class Address {
 
     @Id
-    @GeneratedValue(strategy=GenerationType.IDENTITY)
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private long id;
 
     @Column(nullable = false)
diff --git a/spring-data-rest/src/main/java/com/baeldung/models/Author.java b/spring-data-rest/src/main/java/com/baeldung/models/Author.java
index cdd04cbdcf..3f43af9c47 100644
--- a/spring-data-rest/src/main/java/com/baeldung/models/Author.java
+++ b/spring-data-rest/src/main/java/com/baeldung/models/Author.java
@@ -16,7 +16,7 @@ import javax.persistence.ManyToMany;
 public class Author {
 
     @Id
-    @GeneratedValue(strategy=GenerationType.IDENTITY)
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private long id;
 
     @Column(nullable = false)
diff --git a/spring-data-rest/src/main/java/com/baeldung/models/Book.java b/spring-data-rest/src/main/java/com/baeldung/models/Book.java
index 002a64e738..07b0d08b84 100644
--- a/spring-data-rest/src/main/java/com/baeldung/models/Book.java
+++ b/spring-data-rest/src/main/java/com/baeldung/models/Book.java
@@ -16,14 +16,14 @@ import javax.persistence.ManyToOne;
 public class Book {
 
     @Id
-    @GeneratedValue(strategy=GenerationType.IDENTITY)
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private long id;
 
     @Column(nullable = false)
     private String title;
-    
+
     private String isbn;
-    
+
     @ManyToOne
     @JoinColumn(name = "library_id")
     private Library library;
@@ -63,7 +63,6 @@ public class Book {
         this.isbn = isbn;
     }
 
-
     public Library getLibrary() {
         return library;
     }
diff --git a/spring-data-rest/src/main/java/com/baeldung/models/Library.java b/spring-data-rest/src/main/java/com/baeldung/models/Library.java
index c27512d0e4..091975f5d0 100644
--- a/spring-data-rest/src/main/java/com/baeldung/models/Library.java
+++ b/spring-data-rest/src/main/java/com/baeldung/models/Library.java
@@ -17,7 +17,7 @@ import org.springframework.data.rest.core.annotation.RestResource;
 public class Library {
 
     @Id
-    @GeneratedValue(strategy=GenerationType.IDENTITY)
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private long id;
 
     @Column
diff --git a/spring-data-rest/src/main/java/com/baeldung/models/Subject.java b/spring-data-rest/src/main/java/com/baeldung/models/Subject.java
index b3b9a5b0a0..4e5fa82148 100644
--- a/spring-data-rest/src/main/java/com/baeldung/models/Subject.java
+++ b/spring-data-rest/src/main/java/com/baeldung/models/Subject.java
@@ -10,7 +10,7 @@ import javax.persistence.Id;
 public class Subject {
 
     @Id
-    @GeneratedValue(strategy=GenerationType.IDENTITY)
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private long id;
 
     @Column(nullable = false)
diff --git a/spring-data-rest/src/main/java/com/baeldung/projections/CustomBook.java b/spring-data-rest/src/main/java/com/baeldung/projections/CustomBook.java
index 1cd9c01383..3dc6938f5c 100644
--- a/spring-data-rest/src/main/java/com/baeldung/projections/CustomBook.java
+++ b/spring-data-rest/src/main/java/com/baeldung/projections/CustomBook.java
@@ -8,15 +8,15 @@ import org.springframework.data.rest.core.config.Projection;
 import com.baeldung.models.Author;
 import com.baeldung.models.Book;
 
-@Projection(name = "customBook", types = { Book.class }) 
+@Projection(name = "customBook", types = { Book.class })
 public interface CustomBook {
     @Value("#{target.id}")
-    long getId(); 
-    
+    long getId();
+
     String getTitle();
-    
+
     List<Author> getAuthors();
-    
+
     @Value("#{target.getAuthors().size()}")
     int getAuthorCount();
 }
diff --git a/spring-data-rest/src/main/java/com/baeldung/repositories/BookRepository.java b/spring-data-rest/src/main/java/com/baeldung/repositories/BookRepository.java
index 34019a9d91..eee44f35d4 100644
--- a/spring-data-rest/src/main/java/com/baeldung/repositories/BookRepository.java
+++ b/spring-data-rest/src/main/java/com/baeldung/repositories/BookRepository.java
@@ -7,4 +7,5 @@ import com.baeldung.models.Book;
 import com.baeldung.projections.CustomBook;
 
 @RepositoryRestResource(excerptProjection = CustomBook.class)
-public interface BookRepository extends CrudRepository<Book, Long> {}
+public interface BookRepository extends CrudRepository<Book, Long> {
+}
diff --git a/spring-data-rest/src/main/java/com/baeldung/repositories/SubjectRepository.java b/spring-data-rest/src/main/java/com/baeldung/repositories/SubjectRepository.java
index a91ae2d505..76e34b0799 100644
--- a/spring-data-rest/src/main/java/com/baeldung/repositories/SubjectRepository.java
+++ b/spring-data-rest/src/main/java/com/baeldung/repositories/SubjectRepository.java
@@ -8,8 +8,8 @@ import org.springframework.data.rest.core.annotation.RestResource;
 import com.baeldung.models.Subject;
 
 public interface SubjectRepository extends PagingAndSortingRepository<Subject, Long> {
-    
+
     @RestResource(path = "nameContains")
     public Page<Subject> findByNameContaining(@Param("name") String name, Pageable p);
-    
+
 }
\ No newline at end of file
diff --git a/spring-data-rest/src/test/java/com/baeldung/events/AuthorEventHandlerUnitTest.java b/spring-data-rest/src/test/java/com/baeldung/events/AuthorEventHandlerUnitTest.java
index 6db536c40c..c01d5882a0 100644
--- a/spring-data-rest/src/test/java/com/baeldung/events/AuthorEventHandlerUnitTest.java
+++ b/spring-data-rest/src/test/java/com/baeldung/events/AuthorEventHandlerUnitTest.java
@@ -9,21 +9,21 @@ import static org.mockito.Mockito.mock;
 
 public class AuthorEventHandlerUnitTest {
 
-        @Test
-        public void whenCreateAuthorThenSuccess() {
-                Author author = mock(Author.class);
-                AuthorEventHandler authorEventHandler = new AuthorEventHandler();
-                authorEventHandler.handleAuthorBeforeCreate(author);
-                Mockito.verify(author,Mockito.times(1)).getName();
+    @Test
+    public void whenCreateAuthorThenSuccess() {
+        Author author = mock(Author.class);
+        AuthorEventHandler authorEventHandler = new AuthorEventHandler();
+        authorEventHandler.handleAuthorBeforeCreate(author);
+        Mockito.verify(author, Mockito.times(1)).getName();
 
-        }
+    }
 
-        @Test
-        public void whenDeleteAuthorThenSuccess() {
-                Author author = mock(Author.class);
-                AuthorEventHandler authorEventHandler = new AuthorEventHandler();
-                authorEventHandler.handleAuthorAfterDelete(author);
-                Mockito.verify(author,Mockito.times(1)).getName();
+    @Test
+    public void whenDeleteAuthorThenSuccess() {
+        Author author = mock(Author.class);
+        AuthorEventHandler authorEventHandler = new AuthorEventHandler();
+        authorEventHandler.handleAuthorAfterDelete(author);
+        Mockito.verify(author, Mockito.times(1)).getName();
 
-        }
+    }
 }
diff --git a/spring-data-rest/src/test/java/com/baeldung/events/BookEventHandlerUnitTest.java b/spring-data-rest/src/test/java/com/baeldung/events/BookEventHandlerUnitTest.java
index 28f0b91e1c..d6b8b3b25e 100644
--- a/spring-data-rest/src/test/java/com/baeldung/events/BookEventHandlerUnitTest.java
+++ b/spring-data-rest/src/test/java/com/baeldung/events/BookEventHandlerUnitTest.java
@@ -8,21 +8,21 @@ import org.mockito.Mockito;
 import static org.mockito.Mockito.mock;
 
 public class BookEventHandlerUnitTest {
-        @Test
-        public void whenCreateBookThenSuccess() {
-                Book book = mock(Book.class);
-                BookEventHandler bookEventHandler = new BookEventHandler();
-                bookEventHandler.handleBookBeforeCreate(book);
-                Mockito.verify(book,Mockito.times(1)).getAuthors();
+    @Test
+    public void whenCreateBookThenSuccess() {
+        Book book = mock(Book.class);
+        BookEventHandler bookEventHandler = new BookEventHandler();
+        bookEventHandler.handleBookBeforeCreate(book);
+        Mockito.verify(book, Mockito.times(1)).getAuthors();
 
-        }
+    }
 
-        @Test
-        public void whenCreateAuthorThenSuccess() {
-                Author author = mock(Author.class);
-                BookEventHandler bookEventHandler = new BookEventHandler();
-                bookEventHandler.handleAuthorBeforeCreate(author);
-                Mockito.verify(author,Mockito.times(1)).getBooks();
+    @Test
+    public void whenCreateAuthorThenSuccess() {
+        Author author = mock(Author.class);
+        BookEventHandler bookEventHandler = new BookEventHandler();
+        bookEventHandler.handleAuthorBeforeCreate(author);
+        Mockito.verify(author, Mockito.times(1)).getBooks();
 
-        }
+    }
 }
diff --git a/spring-data-rest/src/test/java/com/baeldung/projection/SpringDataProjectionLiveTest.java b/spring-data-rest/src/test/java/com/baeldung/projection/SpringDataProjectionLiveTest.java
index 702c1521da..ad219ccd53 100644
--- a/spring-data-rest/src/test/java/com/baeldung/projection/SpringDataProjectionLiveTest.java
+++ b/spring-data-rest/src/test/java/com/baeldung/projection/SpringDataProjectionLiveTest.java
@@ -29,16 +29,15 @@ public class SpringDataProjectionLiveTest {
     private static final String BOOK_ENDPOINT = "http://localhost:8080/books";
     private static final String AUTHOR_ENDPOINT = "http://localhost:8080/authors";
 
-
     @Autowired
     private BookRepository bookRepo;
 
     @Autowired
     private AuthorRepository authorRepo;
-    
+
     @Before
-    public void setup(){
-        if(bookRepo.findById(1L) == null){
+    public void setup() {
+        if (bookRepo.findById(1L) == null) {
             Book book = new Book("Animal Farm");
             book.setIsbn("978-1943138425");
             book = bookRepo.save(book);
@@ -48,45 +47,44 @@ public class SpringDataProjectionLiveTest {
             author = authorRepo.save(author);
         }
     }
-    
+
     @Test
-    public void whenGetBook_thenOK(){
-        final Response response = RestAssured.get(BOOK_ENDPOINT+"/1");
-        
+    public void whenGetBook_thenOK() {
+        final Response response = RestAssured.get(BOOK_ENDPOINT + "/1");
+
         assertEquals(200, response.getStatusCode());
         assertTrue(response.asString().contains("isbn"));
         assertFalse(response.asString().contains("authorCount"));
-//        System.out.println(response.asString());
+        // System.out.println(response.asString());
     }
-    
-    
+
     @Test
-    public void whenGetBookProjection_thenOK(){
-        final Response response = RestAssured.get(BOOK_ENDPOINT+"/1?projection=customBook");
-        
+    public void whenGetBookProjection_thenOK() {
+        final Response response = RestAssured.get(BOOK_ENDPOINT + "/1?projection=customBook");
+
         assertEquals(200, response.getStatusCode());
         assertFalse(response.asString().contains("isbn"));
-        assertTrue(response.asString().contains("authorCount"));        
-//        System.out.println(response.asString());
+        assertTrue(response.asString().contains("authorCount"));
+        // System.out.println(response.asString());
     }
-    
+
     @Test
-    public void whenGetAllBooks_thenOK(){
+    public void whenGetAllBooks_thenOK() {
         final Response response = RestAssured.get(BOOK_ENDPOINT);
-        
+
         assertEquals(200, response.getStatusCode());
         assertFalse(response.asString().contains("isbn"));
-        assertTrue(response.asString().contains("authorCount"));    
-       // System.out.println(response.asString());
+        assertTrue(response.asString().contains("authorCount"));
+        // System.out.println(response.asString());
     }
-    
+
     @Test
-    public void whenGetAuthorBooks_thenOK(){
-        final Response response = RestAssured.get(AUTHOR_ENDPOINT+"/1/books");
-        
+    public void whenGetAuthorBooks_thenOK() {
+        final Response response = RestAssured.get(AUTHOR_ENDPOINT + "/1/books");
+
         assertEquals(200, response.getStatusCode());
         assertFalse(response.asString().contains("isbn"));
-        assertTrue(response.asString().contains("authorCount"));    
+        assertTrue(response.asString().contains("authorCount"));
         System.out.println(response.asString());
     }
 }
diff --git a/spring-security-mvc-login/src/main/resources/RedirectionWebSecurityConfig.xml b/spring-security-mvc-login/src/main/resources/RedirectionWebSecurityConfig.xml
index 231b5ab57e..659347f610 100644
--- a/spring-security-mvc-login/src/main/resources/RedirectionWebSecurityConfig.xml
+++ b/spring-security-mvc-login/src/main/resources/RedirectionWebSecurityConfig.xml
@@ -14,7 +14,9 @@
     </http>
 
     <beans:bean class="org.springframework.security.web.authentication.SavedRequestAwareAuthenticationSuccessHandler" name="awareAuthenticationSuccessHandler"/>
-    <beans:bean class="org.baeldung.security.RefererAuthenticationSuccessHandler" name="refererHandler"/>
+    <beans:bean class="com.baeldung.security.RefererAuthenticationSuccessHandler" name="refererHandler"/>
+    <beans:bean class="com.baeldung.controller.SecuredResourceController" />
+    <beans:bean id ="passwordEncoder" class = "org.springframework.security.crypto.password.NoOpPasswordEncoder" factory-method = "getInstance" />
 
     <authentication-manager>
         <authentication-provider>
@@ -26,4 +28,3 @@
 
 
 </beans:beans>
-